Quinone methides substituted at the 7 position are known to inhibit the polymerization of reactive monomers such as styrene. See U.S. Pat. Nos. 5,583,247, 5,750,765 and 7,045,647. More particularly, substituted 7-cyano quinone methides of formula (1) in comparison to the current commercial inhibitor 2,4-dinitro-sec-butylphenol (DNBP) are less toxic, can reduce potential NOx emissions by up to 90% and have improved performance. There is not, however, a practical process for manufacturing substituted 7-cyano quinone methides.